AJAX and Server-Sent Events (SSE): Real-Time Updates in Your Web App

Learn how to use Server-Sent Events with AJAX for live data streaming

Photo by Scott Rodgerson on Unsplash

Server-Sent Events (SSE) provide a simple way to stream data from a server to a web browser in real-time. Unlike long-polling, SSE keeps a persistent connection open, allowing the server to send data to the client as soon as it’s available. This is useful for live notifications, stock prices, or chat applications.

Let’s see how to implement SSE in your web application.

How Server-Sent Events Work

SSE is a one-way communication method where the server sends events to the client over a long-lived connection. The client listens to these events and processes the data as it arrives.

Code Example:

Here’s how you can use Server-Sent Events in JavaScript:

// Create a new EventSource to connect to the server
const eventSource = new EventSource('https://api.example.com/events');

// Function to handle incoming events
eventSource.onmessage = (event) => {
  // Process the incoming data
  console.log('Received event:', event.data);
  
  // Update your web page with the data
  // ...
};

// Handle connection errors
eventSource.onerror = (error) => {…